202 



sists of a main stem, 19 cm. long and 4-5 mm. in diameter, from which two 

 branches arise, one on either side. The lower branch is 9 cm. long and arises 

 at an acute angle. The upper, which is incomplete, measures 4"5 cm. in length. 

 The diameter of the branches is about the same as that of the main stem and 

 is almost uniform throughout their entire length. 



The cojnenchyma is thick and very rugose in appearance, being supported 

 by spicules arranged in all directions. 



The polyps are disposed closely over the whole surface so that very little 

 of the coenenchyma is seen. The verruete are large, measuring 1 mm. in height 

 and I'o mm. in diameter. The surface is covered by the long smooth projections 

 of the spicules, the spiny part being noticeable further down. These projections 

 are directed upwards and outwards and are sometimes curved. They are often 

 disposed in whorls, but at other places are irregularly arranged and give the 

 polyps a very spiny armature. The anthocodife are completely retractile. 

 There is a long oesophageal portion, often extending to a length of 2 mm., of a 

 dark brown colour. The greater number of these are protruded and give the 

 colony a characteristic appearance. There is an elevated conical operculum 

 composed of eight groups of three spindles and a collaret of two or three rows of 

 transversely arranged curved spicules. The " points " consist of two bent spindles 

 which touch foi' over three-quarters of their length but diverge near the collaret, 

 the interspace being almost completely filled by a short, curved, transversely 

 disposed spindle. 



The axis is brown and cylindrical. It is divided into chambers by tranverse 

 septa. The lower portion is firm and flexible, but the upper part is soft and 

 collapsible. It is composed of long strands and wlieu cut longitudinally these 

 strands appear alternately light and dark, giving a peculiarly bright sheen. It is 

 horny in composition and measures 1 75 mm. in diameter at the base. 



The spicules of the coenenchyma are very characteristic — especially those 

 which show a number of smooth spines projecting from one side of a warty 

 spindle. The following are some of the chief types with measurements in 

 millimetres : — 



(a) One smooth spine from the base of which project a number of branch- 

 ing arms irregularly covered with warts : — 



0'55 X 0"35, spine 03 long and 0075 broad at base. 

 0-7 X 0-3, „ 0-4 „ „ 0-08 „ „ „ 

 0-6 X 0-3, „ 0-4 „ „ 0-1 „ „ „ 



0-7x0<3, „ 0-4 „ „ 0-1 „ „ „ 



(ft) Bent thick spindles with irregular warts, 0-6 x 0-2 ; 0-8 x 0'12. 

 (e) Spindle-shaped spicules covered with warts but giving off on one side a 

 number of smooth projecting spines. 



